Evidence of different ${\mathrm{\Lambda }}_{\mathrm{c}}$-baryon and D-meson elliptic flow in Pb$-$Pb collisions at $\sqrt{{\mathit{\text{s}}}_{\mathrm{N}\mathrm{N}}}$ = 5.36 TeV with ALICE at the LHC

The ALICE collaboration reports the azimuthal-anisotropy coefficient $v_2$ of prompt D${}^0$, D${}^{+}$, D${}_{\mathrm{s}}^{+}$ mesons and the first measurement of $v_2$ of prompt ${\mathrm{\Lambda }}_{\mathrm{c}}$ baryons in semicentral Pb$-$Pb collisions at a center-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{N}\mathrm{N}}}=5.36$ TeV. The D mesons and ${\mathrm{\Lambda }}_{\mathrm{c}}$ baryons are reconstructed in their hadronic decays at midrapidity ($\mathrm{\mid }y\mathrm{\mid }<0.8$) in the transverse-momentum interval $0.5<p_{\mathrm{T}}<24$ GeV/$c$. Similar $v_2$ values are measured for D${}^0$ and D${}^{+}$, while a hint of a difference ($2.6\sigma$) emerges between D${}^0$ and D${}_{\mathrm{s}}^{+}$ mesons in the $1<p_{\mathrm{T}}<5$ GeV/$c$ interval. A larger $v_2$ for ${\mathrm{\Lambda }}_{\mathrm{c}}$ baryons with respect to D${}^0$ mesons is observed with $3.7\sigma$ significance for $4<p_{\mathrm{T}}<12$ GeV/$c$, providing evidence for the partonic origin of charm-hadron $v_2$ and hadron formation via quark coalescence. This interpretation is further supported by comparisons with theoretical calculations of charm-quark transport in a hydrodynamically expanding medium.